I got only the username, how to recover a account?

Hi guys i can't login to my 16 years running imdb-account.  i'm pretty certain it used to be connected with my facebook account. not 100% certain though.  apparentely connecting with facebook is not possible anylonger since last year,  and one is supposed to use password reset.   long story short, i doesn't work. i've tried several email addresses, the one i thought it was, it's saying it doesn't have such user, 2 others have randomly by me created imdb accounts associated with it. so, all i got is the username that is shown on reviews.  any idea how i can figure out the email with this information? Is there any email support by imdb?  i'd appreciate if someone could help, there's a lot of history in this account :-(